Machine for the cold form generating of cylindrical workpieces



6 Sheets-Sheet 1 July 11, 1961 A. MEYER ETAL MACHINE FOR THE cow FORMGENERATING CYL ORKPIECES INDRICAL W Filed May 15, 1959 ALBERT MEYER ANDOrro WENGER C 5 m H NV M w 0 Hm w W V. B

July. 11, 1961 A. MEYER ETAL 2,991,672

MACHINE FOR THE cow FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May15. 1959 6 Sheets-Sheet 2 G ALBERT MEYER Aw OTTO WENGER I/ve/ENraRsATTORNEYS July 11, 196 A. MEYER ETAL 2,991,672

MACHINE FOR THE cow FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May15, 1959 6 Sheets-Sheet 3 ALBERT ME YER AND Orro Mensa/2 I N VENTORS BYMMPW ATTORNEYS July 11, 1961 A. MEYER EI'AL MACHINE FOR THE COLD FORMGENERATING OF Filed May 15, 1959 CYLINDRICAL WORKPIECES 6 Sheets-Sheet 4ALBERT MEYER AND OTTO WENGER IMVENTORS July 11, 1961 A. MEYER ETAL2,991,672

MACHINE FOR THE COLD FORM GENERATING 0F CYLINDRICAL WORKPIECES Filed May15. 1959 6 Sheets-Sheet 5 Flig. 12

65 Fig. 11 \1'\ g l ALBERT MEYER AND Orro WENGER INVENTORS 4 BY Wm, M WMATTORNEYS July 11, 1961 A. MEYER EI'AL 2,991,672

MACHINE FOR THE com FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May15. 1959 6 Sheets-Sheet 6 ALBERT MEYER m OTTO u/ENGER INVEH roles By u MATTo RNEVS Unite 2,991,672 MA CHINE FOR THE COLD FORM GENERATING FCYLINDPICAL WURKPECES Albert Meyer, Thalwil, and Dtto Wenger, Zurich,Switzerland, assignors to Maag-Zahurader 8: MaschinenAktiengesellschaft, Zurich, Switzerland Filed May 15, 1959, Ser. No.313,481 Claims priority, application Switzerland May 16, 1953 Claims.(Cl. 80-16) In our copending application Ser. No. 812,509, filed May 11,1959, titled A Method for the Cold Form Generating of Cylindricalworkpieces there is described a method for the cold form generating ofcylindrical workpieces such as 'splined shafts, straight and helicalspur gears as well as other generated profiles without cutting by meansof profiling tools moved relative to the workpiece.

The method is for generating profiles on cylindrical workpieces, theprofiles having raised and depressed portinuously rotating the workpieceabout its central longitudinal axis simultaneously with the movement ofthe cold forming tools, and simultaneously moving the workpiece in thedirection of the longitudinal axis to feed it between the tools.

It is a prime object of the present invention to provide a machine forcarrying out said method.

To this end the machine according to the present invention comprisesdriving means producing a rotary, rolling motion of a workpiece to beprofiled about its longitudinal axis, clamping means for clamping saidworkpiece, generating tools for generating the desired profile in theworkpiece, tool holders adapted to receive said tools and mountedpivotally about an axis intersecting the longitudinal middle axis ofworkpiece, motion transmitting means connected with said driving meansand adapted to move the tool holders with the tools in the direction inwhich profiles being produced extend and in the direction towards andaway from the longitudinal middle axis of the workpiece and means forrotating and feeding the workpiece axially with respect to the Workpiecebetween the latter and the tools.

Other features and advantages of the invention will oecome apparent fromthe description, now to follow, of preferred embodiments thereof, givenby way of example only and in which reference will be made to theaccompanying, partially diagrammatical drawings, in which:

FIG. 1 is a partial longitudinal sectional elevation view through theaxis of the workpiece and a partial cross sectional view of a toolholder, taken along line I-I of FIG. 2;

FIG. 2 is a transverse sectional view through the workpiece showingthree tools and tool holders positioned around the workpiece;

FIG. 3 is partial view of the profile of the workpiece being produced;

FIG. 4 is a view similar to FIG. 2 showing a workpiece having twodiametrally oppositely positioned tools for producing straight spurgears;

FIG. 5 is a longitudinal sectional view taken along line V-V of FIG. 4;

tates Patent G FIG. 6 is a plan view of the arrangement of FIG. 4 seenin the direction of the arrow VI of FIG. 4; 7

'FIG. 7 is a view similar to that of FIG. 6 showing the disposition ofthe tools for forming helical spur gears;

FIGURE 8 shows a partial section of an embodiment of the machineaccording to the invention;

FIGURE 9 is a section taken along the axis Y of a tool holder of themachine according to FIGURE 8;

FIGURE 10 shows a sectional view along the line III-III of the same toolholder as shown in FIGURE 9;

FIGURE 11 is a section taken along the line IVIV in FIGURE 10;

FIGURE 12 illustrates, in a section similar to that of FIGURE 11, amodified embodiment of the tool holder, and

FIGURE 13 illustrates diagrammatically the hydraulic-mechanical controlfor additional motions imparted to the tools and to the workpiece.

Generally speaking, the cold working is carried out by executing a rapidmovement of the cold working tools 1 (FIGS. l-S) relative to theworkpiece A in the direction X (FIG. 1) of the longitudinal axis of theworkpiece, and also moving the tools in the direction Y both toward andaway from the axis of the workpiece. The distance which the tools aremoved toward and away from the axis of the workpiece is less than theheight of the portions of the profile, as shown in FIG. 3, being formed,is. is less than the sum of the radial dimensions of the shaded areas kand m. The workpiece is also continuously rotated around its centrallongitudinal axis and is fed in the direction G (FIG. 1) between thetools 1. The resultant path of the tools relative to the workpiece isthe path C (FIG. 1). The tools themselves can also be rotated abouttheir own axes in the direction indicated by the arrows on the tools 1.

FIG. 2 shows how the tools may be disposed around the workpiece forproducing a spur gear, each of the tools being given a motion asdescribed with reference to FIG. 1.

FIGS. 4 6 show an arrangement of tools and the worle piece for producingspur gears. In addition to the motion given to the tools as describedwith reference to 'FIG. 1, the workpiece can be oscillated in itsmovement around its longitudinal axis, as indicated by the double arrowadjacent the large arrow indicating the rotation, and the tools can beoscillated back and forth along their own axes of rotation, asrepresented by the arrows u and v, this oscillation being synchronizedwith the rotational oscillation of the workpiece. This type of movementenables the tools to produce many diiferent sizes and shapes of teethdepending on the degree of movement.

FIG. 7 shows an arrangement of tools and workpiece similar to that ofFIGS. 4-6 in which the workpiece and tool are given the same type ofmovement. In this instance, however, the axis of the tools has been setat a substantial angle to the longitudinal axis of the workpiece, withthe result that there is formed helically extending teeth rather thanstraight teeth.

The apparatus as disclosed in FIGS. 8l3 is for carrying out the methodas set forth above.

The machine represented in FIGURE 8 comprises a headstock 11 slidablymounted on a horizontal guide Ill and provided with a clamping device12- for clamping a workpiece A. A tailstock 14 with a hydraulic feed 15is mounted in the axis of rotation of and opposite to the headstock 11and on a guide 13' aligned with the guide 10.

In a plane perpendicular to the longitudinal middle axis B of theworkpiece A two rotatably mounted tool holders 3 are provided onopposite sides of said axis, the axes Y of said toolholders beingexactly aligned and being situated in said plane perpendicular to theaxis B of the workpiece.

A motor 16 drives two driving pistons for each toolholder 3 through acam drive, not shown, in housing 17, said pistons imparting to the workpistons 18 and 19 respectively through hydraulic conduits 20 and 21respectively the movement necessary for the tool. This movement is theresultant of the small oscillations in direction of the axis Y of thepiston 18 and consequently of the toolholder 3 as well as oscillationsin the longi tudinal direction of the toothing to be produced, i.e. indirection of the X-axis. Thus the tools 1 execute relative to theworkpiece A a movement C the path of which has the shape of a fiatellipse which rises slightly in the direction in which said tools movealong the workpiece during the forming of the workpiece.

The adjustment of the tool holders in direction of axis Y for thedesired diameter of the workpiece is effected by means of a toothedannular nut 24 arranged in the machine housing which housing is in theform of a pressed frame '22 with tie rods 23. The simultaneousadjustment of the opposite toolholders 3 is effected by means of amanual drive 25 which rotates gears 25a meshed with nuts 24.

A piston 62 being continually exposed to hydraulic pressure serves forthe return movement of the toolholder 3 in direction of axis Y and fortaking up the play.

The tools in the present embodiment are formed by generating wormshaving basic rack for-m (Figures 2, 4 and 10) and rotatably mounted insupports 26 with their axis perpendicular to the pivoting axis Y. Pivots27 of said supports 26 are guided in a slide support 23 slidable on thetool holder 3 perpendicularly to the axis Y and driven by a piston 19.

The support 26 pivotably mounted in the slide support 28 permitsadjusting the pitch angle of the generating worms 1. By pivoting thetool holders 3 about their axis Y the direction of movement of the slidesupport 28 is so adjusted that it coincides exactly with the directionwhich the profile to be produced extends.

The rotary motion of the generating worms 1 is transmitted from thedrive shafts 34 through bevel gears 29, 3t) and 31, 32 (Figure 10) and acardan shaft 33. In order to permit transmission of the rotation of thedrive shafts 34 in spite of the axial oscillations of the toolholderssliding spline shaft joints 35 are provided. The drive shafts 34 of thegenerating worms are rigidly interconnected by a gearing 36 and aconnecting shaft 37. An adjustable clutch 3% permits the adjustment ofthe Worms for obtaining a correct meshing of the teeth with thework-piece (phase adjustment).

Moreover, the generating worms 1 of both tool holders are connectedthrough bevel gearing 39, a shaft 40, bevel gearing 41, a differentialdrive 42, a shaft 43 and bevel gearing ts to a regulating drive 45 whichinsures through an auxiliary motor 46 a uniform rotaton of the tools.

For executing a generating movement between the generating worms 1 andthe workpiece A, i.e. for maintaining a rigid ratio of rotation betweenthese two in accordance with the desired number of teeth on theworkpiece, a further driving train is provided through a shaft 47, apickoif gear group 48, a splined shaft 49 and a dividing gearing 50 inthe headstock 11.

In order to produce a constant feed of the workpiece A in direction ofits longtudinal axis relatively to the tools a feed step gearing 51driven by the splined shaft 49 is provided which is connected forrotation with a 7 feed nut 55 through a hollow shaft 52, a clutch 53 anda gearing 54. By rotating the feed nut a threaded, hollow spindle 56supported bythe headstock 11 is displaced in direction of the axis B ofthe workpiece A.

For generating helical gears an additional rotation of the workpiece Awith'regard to the generating worms 1 in a ratio corresponding-to thefeed is required. This additional rotation is obtained through a shaft57, pickoff gears 58, and a sahf-t 59 with a worm gear 59a on the endthereof which energizes with the input gear of a differential gearing42. When a straight gear tooth is being formed, alternating drive 58 isnot operated and the worm shaft 59 and therefor the bevel gear in thedifferential which is meshed with the worm wheel 59a are inoperative.The shaft 40, through bevel gear 41, drives the differential gears 42and thereby the shaft 43 at half of the speed of the shaft 40. The shaft43 rotates the workpiece A.

In order to introduce into the drive of the workpiece the necessaryadditional rotation for the generating of helical gear systems, thealternating drive 58 is brought into operation and thereby the shaft 43has a motion superimposed on its rotation by the worm wheel 59a and theplanet pinions of the difierential 42. Depending on the direction ofrotation of the gear wheel being generated, this said additionalrotation is positive or negative. The alternating drive 58 is formed asa reversing drive which maintains or reverses the direction of rotationof the shaft 59 with regard to that of the shaft 57.

For rapid adjustments in the direction of the feed there is provided anauxiliary motor 60 driving the shaft 57 directly through a chain drive61.

FIGURES l0 and 11 illustrate a toolholder by means of which anadditional, axial reciprocating movement may be imparted to thegenerating worm. Together with a corresponding oscillating rotary motionof the workpiece this additional reciprocation compensates for possibledeviations from the desired direction of the teeth.

The compensating axial reciprocating movement of the generatingworm isgenerated by a piston 63 which acts on a pinion 64 to move two identicalwedges 65 (tapered in longitudinal direction) in the slide guide of thesupport 28. 1

A further embodiment for obtaining the additional axial, reciprocatingmotion of the generating worms is shown in FIGURE 12 according to whicha piston produces the desired reciprocating movement of the worm througha lever 71 and two wedges 65 which slide in the slide guide of thesupport 28.

As a result of this reciprocating movement an oscillating rotary motionmust be superposed on the constant rotary motion of the workpiece. Themotor 16 produces both movements through a cam drive 75 (FIGURE 13)mounted in the housing 17 and being rotatably adjustable with regard tothe cam drive driving the tool holders 3. The cam drive 75 drives apiston 76 which acts on fluid in a conduit 77 to move the piston 63, andthe cam drive 75 also drives an adjustable lever transmission acting ona piston 78 imparting an axial reciprocating motion to a partial worm 72in the gearing 50 so that the workpiece receives a reciprocating motionthrough a worm gear 73. The oscillation angle may be set by adjustingthe lever transmission 79 according to the diameter of the workpiece.

The feed of the mentioned hydraulic members is carried out through feedconduits 80 and valves 81. 82 designates safety valves. The pressuremedium connections 83, 84 admit pressure fluid to the opposite ends ofthe respective cylinders to cause the return movements of worm 72 and ofthe pistons 63 and 70.

The drive of the oscillating movement C is so synchronized with thereciprocating motion of the generating tools that they execute a gomovement for each alternate movement C of the tools and a returnmovement during the intermediate movements C.

Generally speaking when working with the machine of the invention, theouter part of a cylindrical workpiece A of cold worked metal isrepeatedly exposed to the action of the generating worms 1, whichexecute rapid movements C (FIGURE 1) in directions substantiallyparallel to the axis B of the workpiece A in order to produce thedesired profile on the workpiece, this profile being formed by thegenerating or rollingmotion between the rotating workpiece A and theworm 1.

As the clamping device carrying the workpiece A is slidable on themachine bed in the direction of the profile to be produced, profilelengths corresponding approximately to the stroke of the headstock 11may be produced. Thus, it is possible toproduce long profiled bodieswhich may then be cut up into separate sections.

In order to produce a spur gear by means of the machine according toFIGURE 8 the procedure is as follows:

A cylindrical bar, e.g. a steel rod serves as workpiece A' whose outerdiameter corresponds approximately to the pitch circle of the gear to beproduced. This workpiece is clamped in the clamping device 12, then thegenerating worms 1 are set in the proper position radially of the rod bymeans of the manual adjustment 25 so that the distance between the toothcrest of the tool at the inner end of the stroke thereof in the sense ofthe axis Y, corresponding to the position of these worms shown in FIGURE8 and the workpiece axis B corresponds to the root circle of the gear tobe produced. Moreover, the pitch angle of the generating worms is set bymeans of the slide support 28. For obtaining the desired number of teethon the workpiece the necessary pick-off gears 48 are mounted and for thedesired pitch angle of the toothing the necessary pick-off gears 58 aremounted. Thereupon the motors 16 and 46 are switched on in order to movethe tools so that they execute the movements C in the plane parallel tothe profile to be produced. At the same time the workpiece is fed by theengagement of the clutch 53 for the feed gearing 51 towards the Workingarea between the tools and is rotated about its axis B. This rotation istransmitted to the shafts 5 and therefore to the generating worms bymeans of the described gearing. As soon as the front end surface of theworkpiece enters the range of the operating tools, these form duringeach oscillation a depression in the workpiece. These depressions aredistributed over the whole circumference of the workpiece due to itsrotation and the desired profiles are produced by the feed of theworkpiece. The material displaced by the formation of the grooves formsthe crests of the teeth projecting beyond the pitch circle. By thisrotary oscillating and feeding movements all tools take part inproducing all tooth surfaces, thus insuring an absolute uniformity ofthe workpieces.

For producing helical spur gears the longitudinal axes of the generatingworms 1 are pivoted with regard to the axis B of rotation of theworkpiece A so that the helix lines in the tangential section on theworking side of the worms 1 are aligned with the desired helix angle ofthe gear. The ratio of rotation between the worms 1 and the workpiece Awhich is a whole number multiple remains the same depending on thedesired number of teeth; but the number of rotations of the work must becorrected according to the pitch angle and the feed just as with nor malprofiling machines.

When producing some specific teeth types it has been found that therolling movements of the profiling worms 1 may produce deviation in thework A from the desired direction of the teeth.

This is avoided by an additional, axial reciprocating movement of thegenerating worms produced by the alternative embodiment according toFIGURES l1 and 12 together with the additional oscillating rotation ofthe workpiece about its axis B synchronized with the above movement.

This additional reciprocating movement of the tools takes place in adirection perpendicular to the desired direction of the teeth, i.e.perpendicular to the plane of the movement C (FIGURE 8). It is so setthat the tool executes a go movement perpendicular to the plane of themovement C during alternate movements C, whereas the return movementtakes place during the intermediate movements C.

Wherever the direction of the teeth deviates these axial strikes of thetools are so adjusted that they start before or after the .tool has hitthe work, i.e. before or after commencement of rolling; thus thetools-act longer on one flank of the gear than on the opposite one forcompensating the deviation.

The additional, oscillating rotation of the workpiece correspondsexactly to the axial strokes of the generating worms in the generatingcircle of the toothing to be produced.

The machine described permits the manufacture of rolled profiles in theouter zone of a workpiece and it is possible to produce from generatingworms with a basic rack form any number of teeth together with thesocalled profile corrections (profile displacement). There.- fore, it isno longer necessary, as with the prior art machines, to provide aspecial tool for each number of teeth or each type of tooth.

Another advantage of the described machine lies in the fact that noradial forces are taken up by the workpiece supports on account of theopposite disposition of the tools.

Of course, the machine could also be constructed so that the workpieceis maintained stationary and the feed is imparted to the generatingtools in the direction of the profile.

Of course more than two tools may be disposed concentrically to theworkpiece axis, whereby the pivoting axis of the tools intersect theworkpiece axis in one point.

Consequently, while we have shown and described what are now thought tobe the preferred forms of the invention, it is to be understood that thesame is susceptible of other forms and expressions. Consequently, we donot limit ourselves to the precise structures shown and describedhereinabove, except as hereinafter claimed.

We claim:

1. A machine for cold form generating of profiles on cylindricalworkpieces, said profiles having raised and depressed portionsprogressing along the length of said cylindrical workpiece, by movingcold forming tools relative to the workpiece, said machine comprising aplurality of cold forming tools spaced around the circumference of aworkpiece to be shaped, a plurality of tool holders in which said toolsare mounted, said tool holders being rotatable around axes which areperpendicular to and intersect in the longitudinal axis of saidworkpiece, each of said tools being rotatably mounted in the respectivetool holder for rotation around an axis which is perpendicular to theaxis of rotation of said tool holder, each of said tool holders beingmounted formovement toward and away from the workpiece along the axis ofrotation of the tool holder and along an axis perpendicular to the axisof rotation of the tool holder, clamping means for clamping theworkpiece, a first driving means for moving the clamping means and thetool holders relative to each other rotatably and in the axial directionof said workpiece for feeding the workpiece relative to said tools, saiddriving means being connected to said tools for rotating said tools, anda second driving means connected to said tool holders for moving saidtool holders toward and away from said workpiece along the axes ofrotation of said tool holders and simultaneously in a directionperpendicular to the axes of rotation of said tool holders in timedrelationship to said first driving means, whereby the movement ofcoordinated.

2. A machine as claimed in claim 1, in which the tools are worms andsaid second driving means imparting to the tool holder a motion towardand away from the workpiece which is smaller than the desired profiledepth, and in which said first driving means rotates said worms abouttheir own axis at a speed which has a predetermined ratio to the speedof rotation of the workpiece.

3. A machine as claimed in claim 2, in which the tool holders arearranged in pairs on diametrically opposite sides of the workpiece axis,and said second driving means oscillates them in opposite directions.

work and the movement of the tools is 4. A machine as claimed in claim'1, wherein the generating tools are worms, and saidseconcl drivingmeans drives said tool holders toward and away from the workpiece andalong said workpiece in an elliptical path in a direction opposite tothe directon in which said first driving means rotates said worms, andmeans are connected between said driving means for synchronizing themovements of the workpiece and of the tools.

5. A machine as claimed in claim 4, in which said second driving meanscomprises means for imparting to the worms an additional reciprocatingmovement perpendicular to the plane in which said elliptical path lies,and said first driving means include means for superposing an ReferencesCited in thelfile of this patent i UNITED STATES PATENTS Stiefel Mar.29, 192i Grob et a1. Aug. 23, 1955 FOREIGN PATENTS 7 Switzerland May 14,195 Great Britain May 7, 1958 Germany Aug. 23, 1956

